A home buyer does not get to choose the credit score model. The lender does. That is the catch inside Fannie Mae’s decision to open VantageScore 4.0 to every lender, which the mortgage giant set out in Lender Letter LL-2026-06, dated Sept. 9 and updated Sept. 30.

The letter says “All lenders may use VantageScore 4.0 when originating and selling eligible loans to Fannie Mae,” and Fannie Mae no longer asks for prior approval. For whole loans purchased on or after Oct. 1, 2026, and for loans delivered into mortgage-backed securities with issue dates on or after Oct. 1, the change is in effect.

The question behind the news is whether a different score could help a borrower qualify. The sources do not promise that. What they establish is narrower: the lender will decide whether to run Classic FICO or VantageScore 4.0 on a given loan, and a borrower who wants to know which one is being used has to ask.

Who picks the score

The Federal Housing Finance Agency, which oversees Fannie Mae and Freddie Mac, says on its credit scores page, last updated Oct. 2, that “the Enterprises will allow lenders to determine which credit score model (Classic FICO or VantageScore 4.0) to use on each loan they deliver.” The page does not give borrowers a say in the choice.

The FHFA also says that on Sept. 9 the two companies expanded the availability of VantageScore 4.0 to all approved lenders, “removing the requirement for prior written approval.” Classic FICO stays on the approved list.

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Rules that stayed the same

The new option comes with conditions, and Fannie Mae’s letter spells them out.

• Lenders must request VantageScore 4.0 from each of the three credit repositories, Equifax, Experian and TransUnion, when ordering a new credit report. The FHFA calls this the existing tri-merge requirement and says it kept it in the interim to limit the cost and complexity of the change.
• The same credit score model must be used for all borrowers on a single loan. A couple applying together cannot be scored on different models.
• Loans that are manually underwritten still use Classic FICO only.
• Loans originated with VantageScore 4.0 carry a special delivery code, Special Feature Code 067.

Automated underwriting changed as well. Fannie Mae says its Desktop Underwriter system, version 12.1, has been updated to accept VantageScore 4.0 credit reports.

Pricing and the stated goal

Fannie Mae’s letter says its loan-level price adjustment matrix, the table that sets fees tied to a loan’s risk, “has been updated to include guidance outlining applicable pricing for loans delivered using VantageScore 4.0.” The adjustment figures themselves sit in that matrix.

The push for a second score comes from the top of the housing agencies. When the FHFA announced the new models in April, Director William J. Pulte said in a news release: “We are modernizing credit scoring with more predictive models, helping millions of Americans who responsibly pay rent qualify for mortgages.” The release describes the aim as wider access to homeownership and lower costs through competition among scoring companies.

It also says the Federal Housing Administration permits both new models, VantageScore 4.0 and FICO 10T, for underwriting.

What the change means at the loan desk

For a borrower with an application in progress, almost none of this will show up on paper. The lender pulls three credit reports, scores them under the model it picked, and sends the loan to Fannie Mae with the matching code. The practical effect is for lenders that wanted VantageScore 4.0 but had not been approved to use it.

The effect on any one borrower depends on how that person’s file scores under each model, and nothing in Fannie Mae’s letter or the FHFA’s statements gives a general answer on that.

Asking a lender which score it uses

The question can be put to a mortgage lender directly: which credit score model will be used on this loan, and is it Classic FICO or VantageScore 4.0? A borrower who gets different answers from two lenders can compare them side by side, since each lender decides for itself.

Two points are worth confirming. One is that a joint application is scored under a single model for both borrowers. The other is whether the loan is going through automated underwriting or manual review, because manually underwritten loans still use Classic FICO.

The FHFA keeps its credit score policy on one page, and Fannie Mae’s lender letter holds the specific rules lenders follow, including the Oct. 1 date for purchases and securities deliveries.

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This article was prepared with AI assistance and edited for accuracy against the Fannie Mae and FHFA pages linked above.